Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual era a superfície para o torneio de 10 de maio de 2009?
 ###Tabelas: CREATE TABLE ranking_event_finals:_8_4_titles_4_runner-ups (ranking_event_finals:_8_4_titles_4_runner-ups_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Year INT, Championship VARCHAR, Opponent in the final VARCHAR, Score VARCHAR) CREATE TABLE eliminated_contestants'_weigh-in_results (eliminated_contestants'_weigh-in_results_id AUTO_INCREMENT PRIMARY KEY, Contestant VARCHAR, Starting Weight (kg) INT, Final Weight (kg) INT, Weight Lost (kg) INT, Percentage Lost VARCHAR, Position (out of Eliminated Contestants) VARCHAR) CREATE TABLE r_series_models (r_series_models_id AUTO_INCREMENT PRIMARY KEY, Colt model no. VARCHAR, Name VARCHAR, Stock VARCHAR, Fire control VARCHAR, Rear sight VARCHAR, Forward assist VARCHAR, Case deflector VARCHAR, Barrel length VARCHAR, Barrel profile VARCHAR, Barrel twist VARCHAR, Hand guards VARCHAR, Bayonet Lug VARCHAR, Muzzle device VARCHAR) CREATE TABLE atp_challenger_tour_and_itf_futures_doubles_titles_17 (atp_challenger_tour_and_itf_futures_doubles_titles_17_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Tournament VARCHAR, Surface VARCHAR, Partner VARCHAR, Opponents VARCHAR, Score VARCHAR) CREATE TABLE grammar_and_rules (grammar_and_rules_id AUTO_INCREMENT PRIMARY KEY, Trident VARCHAR, Gecko VARCHAR, WebKit VARCHAR, KHTML VARCHAR, Presto VARCHAR, Prince XML VARCHAR)  
SELECT Surface FROM atp_challenger_tour_and_itf_futures_doubles_titles_17 WHERE Date = may 10, 2009